Thermal oxidation of titanium: Evaluation of corrosion resistance as a function of cooling rate

Commercial pure titanium (CP-Ti) samples were subjected to thermal oxidation (TO) at 650 °C for 14 h and 850 °C for 6 h under different cooling conditions viz. furnace, air, and water cooling. XRD reveals the formation of the rutile phase and α-Ti on the CP-Ti TO at 650 °C and the rutile phase on the CP-Ti TO at 850 °C. On the 650 °C CP-Ti, faster cooling leads to the formation of oxide scales on the surface without spallation whereas on the 850 °C sample, faster cooling conditions lead to the formation of oxide scales with spallation. Electrochemical studies reveal that the faster cooling rate has no deleterious effect on the corrosion resistance of TO CP-Ti at 650 °C for 14 h whereas the faster cooling rate has deleterious effect on the corrosion resistance of TO CP-Ti at 850 °C for 6 h in the 0.9% NaCl solution.